1. Field of the Invention
The present invention relates to a novel hydrophilic photoacid generator which is uniformly dispersed in a resist film and thus improves a line edge roughness of resist patterns, and a resist composition comprising the same.
2. Description of the Related Art
A chemically amplified positive resist composition used for semiconductor microfabrication including a lithographic process contains a photoacid generator containing a compound that generates an acid when light is irradiated thereto.
The photoacid generator absorbs light used for semiconductor patterning processes. Regarding an onium salt generally used as the photoacid generator, a cationic moiety of the onium salt is degraded into a radical form and is present as a different molecular form and an acid is produced at an anionic moiety and the acid diffuses into a resist film during wafer baking after light irradiation.
In such a process, a photoacid generator directly affects resolution and line edge roughness of resists due to various factors such as light-absorbing capacity, acid generation efficiency caused by light absorbance, diffusion capacity of acid generated from anions, and strength of anionic acid.
Also, in order to obtain superior evenness, photoacid generators used for chemically-amplified resist materials should be uniformly dispersed in a resist composition. Accordingly, solubility of photoacid generator in a resist solvent and miscibility thereof with a resin are considerably important. However, conventional photoacid generators do not have superior solubility in resist solvents and excellent miscibility with resin resists, and are difficult to prepare at a low cost.